#!/bin/bash
a=
echo "\$a(null value)=$a"

b="10 20 30"
echo $b

unset b
echo $b

c=10
let c=10+1
echo $c
let c=$c+2
echo $c


d=23
echo $d
e=$d
echo $e
d=`echo Hello`
echo $d
echo $e

#使用$(...)机制进行的变量赋值(除去使用``来赋值的另外一种新方法)
#f1=`ls`
#echo "$f1"
#f2=$(ls)
#echo "$f2"

./enviroment1.sh #import an env
echo $TEST_ENV


echo $0
echo `basename $0` 
#Bash 变量都是字符串
exit 0
